Humidity detection method

Abstract

A humidity detection material includes oxide of at least one metal selected from the group consisting of Mg, Ca, Mn, Fe, Co, Ni, and Cu. The metal oxide is preferably in the form of a porous material. The metal oxide is formed preferably in the form of a thin film on a transparent substrate. The humidity detection material is contacted with water vapor in the presence of a gas such as air, and the optical absorbance of the humidity detection material is measured to detect the humidity. The humidity can be detected by an optical method.

What is claimed is: 
     
       1. A humidity detection method comprising: contacting an oxide of at least one metal selected from the group consisting of Mn, Co, Ni, and Cu with a moisture-containing gas, and   measuring an optical absorbance of said oxide, wherein the optical absorbance varies with the humidity.   
     
     
       2. A humidity detection method comprising: contacting a porous oxide of at least one metal selected from the group consisting of Mn, Co, Ni, and Cu with a moisture-containing gas, and measuring an optical absorbance of said oxide, wherein the optical absorbance varies with the humidity.   
     
     
       3. A humidity detection method comprising: contacting a transparent substrate with an oxide thin film of at least one metal selected from the group consisting of Mn, Co, Ni, and Cu formed thereon with a moisture-containing gas, and   measuring an optical absorbance of said oxide at that oxide, wherein the optical absorbance varies with the humidity.